Machine fixture



Nov. 6, 1934. J}. P. MELCHER ET AL 1,979,897

MACH INE FIXTURE Original Filed 001;. 8, 1950 17 Sheets-Sheet 2 INVENTORS MACHINE FIXTURE Original Filed Oct. 8, 1950 17 Sheets-Sheet 5 NW. 1934- J. P. MELCHER ET AL 1,979,897

MACHINE FIXTURE Original Filed Oct. 8, 1930 17 Sheets-Sheet 4 i: I: ML/107 :l KiT-Jr 111' 101 QQ 4&1? 108 101 ,4. 1 i: :I i 105": :Hl $5 Nov. 6, 1934- J. P; MELCHER El AL MACHINE FIXTURE Original Filed Oct. 8, 1930 17 Sheets-Sheet 5.

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MACHINE FIXTURE Original Filed Oct. 8, 1950 17 Sheets-Sheet 9 Nov. 6, 1934. .J. P. MELCHER ET AL MACHINE FIXTURE Original Filed Oct. 8, 1930 17 Sheets$heet l0 5 i l IM hl l l Hi mm o o o o N INVENTORS Nov. 6, 1934. J. P. MELCHER EF AL MACHINE FIXTURE Original Filed Oct. 8, 1930 17 Sheets-Sheet ll HOW/II I IPQVENTORS M w c a a 9:22am- Nov. 6, 1934. J. P. MELCHER Er AL MACHINE FIXTURE 1'? Sheets-Sheet 15 Original Filed Oct. 8, 1930 VENTORQ MM :5. V g vm zmxzM J/Li ATTORNEYS.

Nov. 6, 1934; Y J. P. MELCHER ET AL 1,979,897

MACHINE FIXTURE Original Filed Oct. 8, 1930 17 SheetsSheet 14 9 ww/mm 1934- J. P. MELCHER Er AL 1,979,897

MACHINE FIXTURE Original Filed Def. 8, 1930 17 Sheets-Sheet l5 HIE/ENE 0R3 W Nov. 6,1934. J. P. MELCHER El AL MACHINE FIXTURE Original Filed Oct. 8, 1930 17 Sheets$heet 16 INVENTORs Pnuednm Patented Nov.- 6, 1934 UNITED STATES momma rrx'ruau John P. Melcher, Pittsburgh, and William D. Cappe, Glenshaw, Pa., assignors to Pittsburgh Valve, Foundry and Construction Company, Pittsburgh, Pa., a corporation of Pennsylvania Application October 8, 1930, Serial No. 487,253

Renewed February 16, 1933 13 Claims.

This invention relates to machine fixtures upon which bodies or objects to be machined may be attached and more particularly to fixtures that may be so manipulated as to permit surfaces or parts lying in angularly disposed planes to be machined without removing the bodies or objects' from the fixtures or without changing the position of such bodies or objects with respect to that part of the fixture to which they may be attached.

In machines such as lathes, either of the .horizontal or the vertical type, the work to be machined is turned and the cutting tool is held stationary. By such an arrangement the surface traversed by the tool lies in a plane perpendicular to the axis of the tool. Where such surfaces lying in parallel planes are to be machined, the work is merely advanced towards or from the tool along a line which is parallel to the axis of the tool.

The machining of parallel surfaces by machines of the type referred to above, as 'a general rule,

does not involve the use of complicated jigs and fixtures for holding the work being machined. The fixtures employed forthis class of work'may be manufactured in large numbers so that a large number of machines may be put in service with assurance that the work completed on each and every machine will be identical for all practical seats of gate valves are to be machined, theprob-- lem of providing suitable fixtures becomes more complicated. This problem becomes more complicated, when,.as at present, the trade requires such accuracy and precision in the machining of valve seats that the valve plugs of such valves may be interchangeable, thus making it unnecessary to carry in stock spare valve plugs for each i and every gate valve of the same size that may be in service.

Fixtures heretofore constructed for machining the valve seats of gate valves do not embody the necessary niceties of construction by which it is possible to have several machines in operation with the assurance that accuracy of work turned out by one machine will be identical to. the accuracy of work produced on each and every other mach'ne. In order that it may be possible to obtain the same degree of accuracy from a large .number of machines, it becomes necessary to devise a method whereby a large number of fixtures may be constructed exactly alike in every detail; and whereby the several parts of each fixture may be assembled in exactly the same manner so that a large number of machines may be utilized with the assurance that the work produced by the several machines will be exactly alike within plus or minus one thousandth of an inch in accuracy.

The bodies of gate valves, as known to the art, are provided with circular valve seats located in angularly disposed planes. The angles which such planes make with respect to a fixed plane located between the valve seatsare as a general rule equal.

The valve passages surrounded by the valve seats are opened and closed by a valve plug, the opposite faces of which are parallel to the valve seats. Unless the valve seats are so formed that they are parallel to and disposed at the same angle as the angularly disposed faces of the valve plug, a leaky valve results. As leaky valves are not acceptable to the trade, such valves must either be discarded or machined over again and this necessarily entails loss of production, increased labcr and material costs.

'An object of this invention is the provision of a, machine fixture whereby surfaces located in a pluralityof planes whether parallel or disposed at angles to each other may be machined without removing the body containing such surfaces, from the fixture to which they are attached.

A further object of the invention is to provide a fixture in which a plurality of angularly disposed surfaces may be machinedin articles of trade, such as gate valve bodies, with such precision that the angle at which the various surfaces are machined will be identical in allof the valve bodies within very close limits so that valve plugs may be used interchangeably therewith or the valve bodies may be used interchangeably with the valve plugs thereby making it possible for the consumer to carry a minimum number of spare parts for any given line of valves.

A still further object of the invention is to; provide a method for making-machine fixtures of the type referred to above whereby any number of such fixtures may be constructed, each fixture being an exact duplicate of another so that the work produced by one fixture will be exactly like the work produced by any other fixture.

Other objects of the invention will, in part, be apparent and will, in part, be obvious from the following description taken in conjunction with the accompanying drawings in which:

Figure 1 is a view in longitudinal vertical section of a gate valve which is illustrated for the purpose of clarifying the manner in which the invention may be utilized and of setting forth 2 nevaaov arranged and constructed in accordance with the invention;

Fig. 6 is a fragmentary view in section taken on line VI-VI of Fig. 5;

Fig. '7 is a fragmentary view in section taken on line VIIVII of Fig. 5 illustrating the position and arrangement of a locking device arranged and constructed in accordance withv the invention;

Fig. 8 is a longitudinal viewof a detail embodied in the locking devices of the fixture shown in Fig. 5 and illustrated in the sectional view of Fig. 7;

Fig. 9 is an end view of the detail illustrated in Fig. 8;

Fig. 10 is a fragmentary view of a portion of the fixture shown in Fig. 5 looking in the direction of line X-X thereof;

Fig. 11 is a fragmentary view of a wedge plate embodied in the fixture shown in Fig. 5 looking in the direction of line X[-XI;

Fig. 12 is a top plan view of a locking plate embodied in the locking devibes of the fixture shown in Fig. 5 and illusrated in Fig. '2;

Fig. 13 is a view in front elevation of the looking plate shown inFig. 12;

Fig. 14 is an enlarged end view of a block-embodied in the locking devices of the fixture shown in Fig. 5 and illustrated in section in Fig. 7;

Fig. 16 is a view in section of the fixture shown in Fig. 5 taken on line XVIXVI thereof;

Fig. 17 is a view in section of a supporting or base plate embodied in the fixture and illustrated in section in Fig. 16;

Fig. 18 is a longitudinal view of an index pin embodied in the fixture shown in Flgs. 5 and 16; Fig. 19 is an end view of the index pin; Fig. 20 is an end view of a bushing foraccommodating the index pin illustrated in Figs. 18

and.-19;

Fig. 21 is a view in longitudinal section of the bushing shown in Fig. 20 taken on the line XX[XXI- thereof; M V j Fig. 22 is a top plan view of the supporting or base plate shown in Fig. 17;

Fig; 23 is an edge view of the plate shown in Fig. 22; 1

Fig. 23a is a side view in elevation of a T- shaped nut adapted for use in the plate shown in Figs. 22 and 23;

Fig. 231) is a view in section of the nut taken on line A-A of Fig. 23a;

Fig. 24 is a top plan view of a wedge plate which is arranged to be slidably mounted in the supporting or base plate shown in Figs. 16, 17, 22

and. 23; Fig. 25 is a view in section of the wedge plate shown in Fig. 24 taken on line XXV-XXV thereof; 1

Fig. 26 is a top plan view of a wedge plate which is arranged for-mounting'on the wedge plate shown inFigs. 24 and 25;

.Fig. 27 is a view in section of the plate shown in Fig. 26 taken on line XXVII--XXVII thereof;

Fig. 28 is a top plan view of an index ring arranged for mounting in a groove formed in the plates shown in Figs. 24, 25, 26 and 27;

Fig. 29 is an edge view of the index ring shown in Fig. 28;

Fig. 39 is a view in section of the ring taken on line m xxx of Fig. 28;

Fig. 31 is a top plan view of a clamping ring for clamping the plate shown in Figs. 26 and 27 to the wedge plate shown in Figs. 24 and 25;

Fig. 32 is a view in section of the clamping ring taken on line XXXII-XXXII of Fig. 31;

33 is a top plan view of a face plate to which the valve body of Fig. 1 may be attached, this plate being arranged for mounting on the wedge plate shown in Figs. 26 and 27 Fig. 34 is a view in section taken on line XXXflf-XXXIV of Fig. 33;

Fig. 35 is an edge plan view of the fme or end plate shown in Fig. 33;

Fig. 35 is a view in section of the wedge plate shown in Fig. 24 taken on line XXXVI-XXXVI thereof;

Fig. 3'7 is a top plan view of a clamping ring for clamping the face plate of Figs. 33 to 35 to the wedge plate of Figs. 26, 27 and 36;

Fig. 38 is a view in section of the clamping ring taken on line XXXVIII+XXXVIII of Fig. 37;

Fig. 39 is a top plan view of a modified form of machine fixture assembly arranged and constructed in accordance with the invention;

Fig. 40 is a view in section taken on line XL-XL of Fig. 39; Fig. 40a is a partial enlarged view taken on line XlZr-XL of Fig. 39;

Figs. 41 and 42 are fragmentary views in section taken on lines XLI-XLI and XLII-XLII, respectively, of Fig. 39;

Fig. 43 is a top plan view of a wedge plate embodied in the assembled machine fixture shown in Figs. 39 and 40;

Fig. 44 is a view in section of the wedge plate of Fig. 43 taken on line XLIV-XLIV thereof;

Figs. 45, 46 and 47 are fragmentary views in section taken on lines XLV--XLV, XI.|VI---XI..VI and XLVII-XLVII of Fig. 43;

wedge plate arranged for mounting on the wedge plate shown in Figs. 43 and 44;

Fig. 49 is a view in section taken on line XLIXXLIX of Fig. 48;

Fig. 48 is a top plan view of an intermediate Fig. 50 is a. fragmentary edge view of the plate 7 shown in Fig. 48 taken along lines L--L thereof;

Fig. 51 is a fragmentary view in section taken along line LI-LI of Fig. 48;

Figs. 52 and 53 are edge. and top plan views, respectively, of a face plate arranged for mounting on the wedge plate shown in Figs. 48 and 49;

Fig. 54 is a view in section of the face plate shown in Figs. 52 and 53 taken on lines LIV-LIV of Fig. 53;

Fig. 55 is a fragmentary view in section taken on,line LV-LV of Fig. 53;

Fig.56 is a top plan view of a clamping ring for clamping the face plate shown in Figs. .52,

53' and 54 to the wedge plate shown in Figs. 4a

Fig. 59 is a top plan view of a clamping ring for clamping, the wedge plate shown in Figs. 48

and LXII-LXII, respectively, of Fig. 59;

Fig. 63 is a top plan view of a bearing plate for a wedge associated with the wedge plate of Figs. 43 and 49;

Fig. 64 is .a view in section of the bearing plate of Fig. 63 taken on line LXIV-LXIV thereof;

Figs. 65 and 66 are top plan and sectional views, respectively, of a bearing plate for a wedge associated with the wedge plate of Figs. 43 and 44, thesectional view of Fig. 66 being taken on line LXVI-.-LXVI of Fig. 65;

Figs. 67 and 68 are top plan and edge views, respectively, of a detail embodied in the sectional assembly view ofFig. 40;

Fig. 69 is a view in section taken along line LXIXLXIX of Fig. 67;

Figs. '70, 71 and '72 are top plan and edge elevational views, respectively, of. wedges em:-

bodied in the sectional assembly view of Fig. 40; and

Figs. 78 and "79 are longitudinal and end plan views, respectively, of details employed for operating the wedges illustrated in Figs. to 77, respectively.

Throughout the drawings and the specification like reference characters indicate like parts.

Since the machine fixtures arranged and constructed in accordance with the invention, as illustrated in the assembled and detail views of Figs. 5 to 79, inclusive, are employed for machining surfaces of the valve body illustrated in Fig. 1, a brief description of the valve body and the surfaces to be machined will be given in order that the problem involved in the machining of such surfaces may be understood.

In Fig. 1 of the drawings,- a valve body 1 is shown having a passageway 2 through which fluids, such as water, steam, etc. may pass. At the opposite ends of the passageway flanges 3 and 4 areprovided-for attaching the valve body to pipes or conduits of a pipe line. The valve body is provided also with the usual neck or housing 5 within which a valve stem 6 and a valve plug 7 may operate to open and close the valve., The opposite faces of the valve plug '7 are provided with rings 8 and- 8', of bronze or other suitable material, that cooperate with rings 9 and 9' forming the valve seats, to provide a means for obtaining a fluid-tight joint between the rings 89 and 8-9 when the valve plug is in the closed position.

As shown in Fig. 1, the rings 9 and 9 are mounted in annular recesses 10 and 10' and have screw thread engagement therewith as indicated at 11 and 11'. The recesses in which the rings 9 and 9' are disposed a e usually inclined at an angle with respect to the longitudinal axis 12' of the valve plug and stem. This angle is such that the seating surfaces on the rings 9 and 9' will be parallel to the seating surfaces of the rings 8 and 8 carried by the valve plug 7. In order that a fluid-tight valve may be obtained, .the recesses 10 and 10' must be so accurately formed in the valve body that the valve seats 9 and 9 may be disposed therein at the proper angle to obtain a fluid-tight valve when the valve plug is in the closed position. With reference to the particular valve shown in Fig. 1, it will be observed that the circular recesses 10 and 10 are disposed atan angle 2a to the axis 12 of the valve 41.; (see Figs. 1 and 2 to 4, inclusive).

In order that the surfaces 13 and 14 on the flanges 3 and 4, the valve seat recesses 10 and 10' and the ribs which guide thevalve plug 7 may be machined with such accuracy that the valve plug of one valve of a particular size may be used interchangeably with other valves of the same size, a machine fixture M. F., illustrated schematically in Figs. 2, 3 and 4, is provided. The fixture F. is of such form, construction and arrangement that the surfaces 13 and 14 of the flanges 3 and 4 may be machined parallel to each other, the guide ribs for the-valve plug may be machined and'the valve seat recesses 10 and 10' may be formed with such degree of accuracy that the surfaces of all valve bodies finished on fixture M. F. will be identical within plus or minus one one-thousandth of an inch in degree of accuracy.

In order that a large number of fixtures M. F. may be constructed so that one fixture will be exactly like any of the other fixtures thereby ,making it possible to have a large number of machines producing the same class of work, and so that the work produced on one machine will be identical in accuracy to the work produced on any other machine, a novel method has been devised for constructing such fixtures. This method will be described in detail in a subsequent section of the specification.

I body and that the angle between the recesses is l The machine fixture M. F. as schematically illustrated in Figs. 2, 3 and 4, comprisestaper plates 17 and 18 and a face plate 19 to which the valve body 1 is clamped. The plates 17, 18 and 19 are preferably of circular form and of such thickness that the plates shall not bend or lose their shape when subjected to stresses or loads.

With reference to Fig.2, it will be observed that face' 20 of plate 17 is inclined or tapered at an angle a to the bottom, face 21; likewise, face angles 2a, respectively, with the faces 25, 23 and 21 of the said plates. Also, when the plates 17, 18 and 19 .arein the position shown'in Fig. 2, the flanges 3 and 4 of the valve body are parallel to faces 25, 24, 23 and 21 of the plates.

It will be understood that the fixture M. F. is arranged for mounting either on the spindle of the horizontal type lathe or upona rotatable table of a vertical type machine, as, for example, a machine known to the trade as the Bullard vertical turret lathe. In Figs. 2, 3 and 4 the fixture M. F. is shown in connection with the horizontal type lathe. The plate 17 is shownas attached to a plate 89 secured to a spindle 26 of a lathe (not shown). so that the fixture may be rotated about the axis of rotation of the spindle. As il- 

